Camino Verde (The Green Way): evidence-based community mobilisation for dengue control in Nicaragua and Mexico: feasibility study and study protocol for a randomised controlled trial

Preferences and Demand for Mosquito Control among Dengue-Endemic Communities in Peñuelas, Puerto Rico: An Application of the Best-Worst Choice Model

Aedes aegypti is the primary vector of dengue virus and threatens 3.9 billion people living in many tropical and subtropical countries. Prevention and reduction of dengue and other Aedes-borne viruses, including Zika and chikungunya, requires control of mosquito populations. Community mobilization and input are essential components of vector control efforts. Many vector control campaigns do not engage communities prior to implementation, leading to program failure. Those that do often conduct basic knowledge, attitude, and practice surveys that are not designed to explicitly elicit preferences. Here, we applied a novel stated preference elicitation tool, best-worst choice, to understand preferences, willingness to participate, and willingness to pay for mosquito control in dengue-endemic communities of Peñuelas, Puerto Rico. Findings revealed that the community preferred mosquito control programs that are 1) applied at the neighborhood level, 2) implemented by the local government, and 3) focused specifically on reducing disease transmission (e.g., dengue) instead of mosquito nuisance. Programs targeting the reduction of disease transmission and higher educational level of participants increased willingness to participate. Participants were willing to pay an average of $72 annually to have a program targeting the reduction of diseases such as dengue. This study serves as a model to engage communities in the design of mosquito control programs and improve stakeholders' decision-making.

A protocol for evaluating the entomological impact of larval source reduction on mosquito vectors at hotel compounds in Zanzibar

There is an increasing awareness of the association between tourism activity and risks of emerging mosquito-borne diseases (MBDs) worldwide. In previous studies we showed that hotels in Zanzibar may play an important role in maintaining residual foci of mosquito vectors populations of public health concern. These findings indicated larval sources removal (LSR) interventions may have a significant negative impact on vector communities. However, a thorough analysis of the response vector species to potential LSM strategies must be evaluated prior to implementation of a large-scale area-wide control campaign. Here we propose a protocol for evaluation of the impact of LSR against mosquito vectors at hotel settings in Zanzibar. This protocol is set to determine the efficacy of LSR in a randomized control partial cross-over experimental design with four hotel compounds representing the unit of randomization for allocation of interventions. However, the protocol can be applied to evaluate the impact of LRS in more than four sites. Proposed interventions are active removal of disposed containers, and installation of water dispenser to replace single use discarded plastic water bottles, which were identified as the most important source of mosquitoes studied hotels. The ideal time for allocating intervention to the intervention arms the dry season, when the mosquito abundance is predictably lower. The possible impact of interventions on mosquito occurrence and abundance risks is then evaluated throughout subsequent rainy and dry seasons. If an appreciable reduction in mosquito abundance and occurrence risks is observed during the trial period, intervention could be extended to the control arm to determine whether any potential reduction of mosquito density is reproducible. A rigorous evaluation of the proposed LRS interventions will inspire large scale trials and provide support for evidence-based mosquito management at hotel facilities in Zanzibar and similar settings.

EVITA Dengue: a cluster-randomized controlled trial to EValuate the efficacy of Wolbachia-InfecTed Aedes aegypti mosquitoes in reducing the incidence of Arboviral infection in Brazil

Background

Arboviruses transmitted by Aedes aegypti including dengue, Zika, and chikungunya are a major global health problem, with over 2.5 billion at risk for dengue alone. There are no licensed antivirals for these infections, and safe and effective vaccines are not yet widely available. Thus, prevention of arbovirus transmission by vector modification is a novel approach being pursued by multiple researchers. However, the field needs high-quality evidence derived from randomized, controlled trials upon which to base the implementation and maintenance of vector control programs. Here, we report the EVITA Dengue trial design (DMID 17-0111), which assesses the efficacy in decreasing arbovirus transmission of an innovative approach developed by the World Mosquito Program for vector modification of Aedes mosquitoes by Wolbachia pipientis.

Methods

DMID 17-0111 is a cluster-randomized trial in Belo Horizonte, Brazil, with clusters defined by primary school catchment areas. Clusters (n = 58) will be randomized 1:1 to intervention (release of Wolbachia-infected Aedes aegypti mosquitoes) vs. control (no release). Standard vector control activities (i.e., insecticides and education campaigns for reduction of mosquito breeding sites) will continue as per current practice in the municipality. Participants (n = 3480, 60 per cluster) are children aged 6–11 years enrolled in the cluster-defining school and living within the cluster boundaries who will undergo annual serologic surveillance for arboviral infection. The primary objective is to compare sero-incidence of arboviral infection between arms.

Discussion

DMID 17-0111 aims to determine the efficacy of Wolbachia-infected mosquito releases in reducing human infections by arboviruses transmitted by Aedes aegypti and will complement the mounting evidence for this method from large-scale field releases and ongoing trials. The trial also represents a critical step towards robustness and rigor for how vector control methods are assessed, including the simultaneous measurement and correlation of entomologic and epidemiologic outcomes. Data from this trial will inform further the development of novel vector control methods.

Trial registration

ClinicalTrials.govNCT04514107. Registered on 17 August 2020

Primary sponsor: National Institute of Health, National Institute of Allergy and Infectious Diseases

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-05997-4.

Effects of consumers and health providers working in partnership on health services planning, delivery and evaluation

BACKGROUND

Health services have traditionally been developed to focus on specific diseases or medical specialties. Involving consumers as partners in planning, delivering and evaluating health services may lead to services that are person-centred and so better able to meet the needs of and provide care for individuals. Globally, governments recommend consumer involvement in healthcare decision-making at the systems level, as a strategy for promoting person-centred health services. However, the effects of this 'working in partnership' approach to healthcare decision-making are unclear. Working in partnership is defined here as collaborative relationships between at least one consumer and health provider, meeting jointly and regularly in formal group formats, to equally contribute to and collaborate on health service-related decision-making in real time. In this review, the terms 'consumer' and 'health provider' refer to partnership participants, and 'health service user' and 'health service provider' refer to trial participants. This review of effects of partnership interventions was undertaken concurrently with a Cochrane Qualitative Evidence Synthesis (QES) entitled Consumers and health providers working in partnership for the promotion of person-centred health services: a co-produced qualitative evidence synthesis.

OBJECTIVES

To assess the effects of consumers and health providers working in partnership, as an intervention to promote person-centred health services.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, PsycINFO and CINAHL databases from 2000 to April 2019; PROQUEST Dissertations and Theses Global from 2016 to April 2019; and grey literature and online trial registries from 2000 until September 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), quasi-RCTs, and cluster-RCTs of 'working in partnership' interventions meeting these three criteria: both consumer and provider participants meet; they meet jointly and regularly in formal group formats; and they make actual decisions that relate to the person-centredness of health service(s).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened most titles and abstracts. One review author screened a subset of titles and abstracts (i.e. those identified through clinical trials registries searches, those classified by the Cochrane RCT Classifier as unlikely to be an RCT, and those identified through other sources). Two review authors independently screened all full texts of potentially eligible articles for inclusion. In case of disagreement, they consulted a third review author to reach consensus. One review author extracted data and assessed risk of bias for all included studies and a second review author independently cross-checked all data and assessments. Any discrepancies were resolved by discussion, or by consulting a third review author to reach consensus. Meta-analysis was not possible due to the small number of included trials and their heterogeneity; we synthesised results descriptively by comparison and outcome. We reported the following outcomes in GRADE 'Summary of findings' tables: health service alterations; the degree to which changed service reflects health service user priorities; health service users' ratings of health service performance; health service users' health service utilisation patterns; resources associated with the decision-making process; resources associated with implementing decisions; and adverse events.

MAIN RESULTS

We included five trials (one RCT and four cluster-RCTs), with 16,257 health service users and more than 469 health service providers as trial participants. For two trials, the aims of the partnerships were to directly improve the person-centredness of health services (via health service planning, and discharge co-ordination). In the remaining trials, the aims were indirect (training first-year medical doctors on patient safety) or broader in focus (which could include person-centredness of health services that targeted the public/community, households or health service delivery to improve maternal and neonatal mortality). Three trials were conducted in high income-countries, one was in a middle-income country and one was in a low-income country. Two studies evaluated working in partnership interventions, compared to usual practice without partnership (Comparison 1); and three studies evaluated working in partnership as part of a multi-component intervention, compared to the same intervention without partnership (Comparison 2). No studies evaluated one form of working in partnership compared to another (Comparison 3). The effects of consumers and health providers working in partnership compared to usual practice without partnership are uncertain: only one of the two studies that assessed this comparison measured health service alteration outcomes, and data were not usable, as only intervention group data were reported. Additionally, none of the included studies evaluating this comparison measured the other primary or secondary outcomes we sought for the 'Summary of findings' table. We are also unsure about the effects of consumers and health providers working in partnership as part of a multi-component intervention compared to the same intervention without partnership. Very low-certainty evidence indicated there may be little or no difference on health service alterations or health service user health service performance ratings (two studies); or on health service user health service utilisation patterns and adverse events (one study each). No studies evaluating this comparison reported the degree to which health service alterations reflect health service user priorities, or resource use. Overall, our confidence in the findings about the effects of working in partnership interventions was very low due to indirectness, imprecision and publication bias, and serious concerns about risk of selection bias; performance bias, detection bias and reporting bias in most studies.

AUTHORS' CONCLUSIONS

The effects of consumers and providers working in partnership as an intervention, or as part of a multi-component intervention, are uncertain, due to a lack of high-quality evidence and/or due to a lack of studies. Further well-designed RCTs with a clear focus on assessing outcomes directly related to partnerships for patient-centred health services are needed in this area, which may also benefit from mixed-methods and qualitative research to build the evidence base.

Reducing mosquito-borne disease transmission to humans: A systematic review of cluster randomised controlled studies that assess interventions other than non-targeted insecticide

BACKGROUND

Mosquito control interventions are widely used to reduce mosquito-borne diseases. It is unclear what combination of interventions are most effective in reducing human disease. A novel intervention study for Buruli ulcer targeting mosquito vectors was proposed for a Buruli ulcer-endemic area of Victoria, Australia. The local community expressed a preference for avoiding widespread residual spraying of pyrethroids. To inform the design of a future cluster randomised control study (cRCT) for Buruli ulcer prevention in Victoria, we conducted a systematic literature review.

AIMS

The aim was to describe cRCT designs which investigated interventions other than non-targeted insecticide for reducing mosquito-borne disease transmission, and comment on the strengths and weaknesses of these study designs.

METHODS

Five medical research databases were searched for eligible literature from the earliest available sources up to 5 July 2019 (Medline, Embase, Web of Science, EBM Reviews, CAB Direct). Reference lists of identified studies were hand searched. Eligible studies were cRCTs using targeted chemical or biological mosquito control interventions, or mosquito breeding source reduction, with the occurrence of mosquito-borne disease as an outcome.

RESULTS

Eight eligible cRCTs, conducted between 1994-2013 were identified in a variety of settings in the Americas and Asia. Interventions to reduce dengue transmission were mass adult trapping and source reduction. Interventions to reduce malaria transmission were largescale larvicide administration and (topical and spatial) repellent use. Three studies showed the intervention was associated with statistically significant reductions in the disease of interest and entomological indicators. High community engagement with the intervention were common to all three. In two studies, large buffer zones reduced contamination between study arms. Heterogeneity was reduced through increasing study cluster numbers, cluster matching and randomisation.

CONCLUSION

High community engagement is vital for a cRCT reducing mosquito-borne disease with a mosquito control intervention. These findings support a mosquito breeding source reduction intervention for Aedes control in a future study of Buruli ulcer prevention if local communities are supportive and very engaged. Regular administration of larvicide to sites unsuited to source reduction may supplement the intervention.

A Realist Synthesis of Community-Based Interventions in Vector-Borne Diseases

Randomized control trials have provided evidence that some community-based interventions (CBIs) work in vector-borne diseases (VBDs). Conversely, there is limited evidence on how well those CBIs succeed in producing specific outcomes in different contexts. To conduct a realist synthesis for knowledge translation on this topic, we examined the extent to which realist concepts (context, mechanisms, and outcomes) and their relationships are present in the existing literature on CBIs for VBDs. Articles on CBIs were identified from prior scoping reviews of health interventions for VBDs. Content of the articles was extracted verbatim if it referred either to realist concepts or CBI features. The number of articles and the average number of words extracted per category per CBI were quantified. Content of the articles was scrutinized to inductively gather qualitative evidence on the interactions between realist concepts. We reviewed 41 articles on 17 CBIs from 12 countries. The average number of words used for mechanisms was much lower than those used for outcomes and context (309,474, and 836, respectively). The average number of words used for mechanisms increased when a CBI was described in three or more articles. There were more extensive accounts on CBI features than on mechanisms. It was difficult to gather evidence on the interactions among realist concepts from the content of the articles. Scarce reporting on mechanisms in published articles limits conducting a realist synthesis of CBIs in VBDs. More transdisciplinary research that goes beyond the biomedical paradigm is needed to boost the development of intervention mechanisms in this field.

How to engage communities on a large scale? Lessons from World Mosquito Program in Rio de Janeiro, Brazil

One of the pillars of the World Health Organization’s (WHO) Global Vector Control Response 2017–2030 strategy is the engagement of communities. Among the priority activities, defined by 2022 by the WHO, is the development of plans for the effective engagement and mobilisation of communities in vector control. Novel technologies for arboviruses control are being developed, such as the Wolbachia method, implemented by the World Mosquito Program (WMP). Here we discuss and analyse the framework for community engagement implemented by the WMP in Brazil, during the large-scale deployment of the method in the municipalities of Niterói and Rio de Janeiro, Brazil. Our experience indicates that the community engagement work for arboviruses control should be understood as an opportunity for local development. It is necessary, based on an integrated analysis of the territory, to understand that the actions for arboviruses control could be a catalyst for the necessary socioenvironmental, cultural and public health changes. Furthermore, it is essential to understand that community engagement goes beyond informing or asking for population consent, but it constitutes a possibility for dialogue and exchange between the various stakeholders present in the territories, to build on cooperation for mosquito-borne disease control.

How to engage communities on a large scale? Lessons from World Mosquito Program in Rio de Janeiro, Brazil

One of the pillars of the World Health Organization's (WHO) Global Vector Control Response 2017-2030 strategy is the engagement of communities. Among the priority activities, defined by 2022 by the WHO, is the development of plans for the effective engagement and mobilisation of communities in vector control. Novel technologies for arboviruses control are being developed, such as the Wolbachia method, implemented by the World Mosquito Program (WMP). Here we discuss and analyse the framework for community engagement implemented by the WMP in Brazil, during the large-scale deployment of the method in the municipalities of Niterói and Rio de Janeiro, Brazil. Our experience indicates that the community engagement work for arboviruses control should be understood as an opportunity for local development. It is necessary, based on an integrated analysis of the territory, to understand that the actions for arboviruses control could be a catalyst for the necessary socioenvironmental, cultural and public health changes. Furthermore, it is essential to understand that community engagement goes beyond informing or asking for population consent, but it constitutes a possibility for dialogue and exchange between the various stakeholders present in the territories, to build on cooperation for mosquito-borne disease control.

Utility of entomological indices for predicting transmission of dengue virus: secondary analysis of data from the Camino Verde trial in Mexico and Nicaragua

Dengue vector entomological indices are widely used to monitor vector density and disease control activities. But the value of these indices as predictors of dengue infection is not established. We used data from the impact assessment of a trial of community mobilization for dengue prevention (Camino Verde) to examine the associations between vector indices and evidence of dengue infection and their value for predicting dengue infection levels. In 150 clusters in Mexico and Nicaragua, two entomological surveys, three months apart, allowed calculation of the mean Container Index, Breteau index, Pupae per Household Index, and Pupae per Container Index across the two surveys. We measured recent dengue virus infection in children, indicated by a doubling of dengue antibodies in paired saliva samples over the three-month period. We examined the associations between each of the vector indices and evidence of dengue infection at household level and at cluster level, accounting for trial intervention status. To examine the predictive value for dengue infection, we constructed receiver operating characteristic (ROC) curves at household and cluster level, considering the four vector indices as continuous variables, and calculated the positive and negative likelihood ratios for different levels of the indices. None of the vector indices was associated with recent dengue infection at household level. The Breteau Index was associated with recent infection at cluster level (Odds ratio 1.36, 95% confidence interval 1.14–1.61). The ROC curve confirmed the weak predictive value for dengue infection of the Breteau Index at cluster level. Other indices showed no predictive value. Conventional vector indices were not useful in predicting dengue infection in Mexico and Nicaragua. The findings are compatible with the idea of sources of infection outside the household which were tackled by community action in the Camino Verde trial.

Vector control is the basis of preventing dengue virus infection. Measurement of dengue vector indices is widely used to monitor dengue control activities, but their utility as predictors of dengue infection is not clear. We used data about vector indices and evidence of recent dengue virus infection from a trial of community mobilization for dengue prevention in Mexico and Nicaragua (Camino Verde), to examine how four standard vector indices could predict dengue infection. Only the Breteau index was associated with evidence of dengue infection, and that only at cluster level. Receiver operating characteristic (ROC) curves confirmed the Breteau Index was only a weak predictor of infection at cluster level; none of the other indices had predictive value. These findings indicate that the four entomological indices studied were not useful predictors of dengue infection. The results are compatible with the idea of sources of infection outside the household which were tackled by community action in the Camino Verde trial.

Analysis of the implementation of a community-based intervention to control dengue fever in Burkina Faso

BACKGROUND

A community-based dengue fever intervention was implemented in Burkina Faso in 2017. The results achieved vary from one area to another. The objective of this article is to analyze the implementation of this intervention, to better understand the process, and to explain the contextual elements of performance variations in implementation.

METHODOLOGY

The research was conducted in the former sector 22 of the city of Ouagadougou. We adapted the Consolidated Framework for Implementation Research (CFIR) to take into account the realities of the context and the intervention. The data collected from the participants directly involved in the implementation using three techniques: document consultation, individual interview, and focus group.

RESULTS

Two dimensions of CFIR emerge from the results as having had a positive influence on the implementation: (i) the characteristics of the intervention and (ii) the processes of the intervention implementation. The majority of the CFIR constructions were considered to have had a positive effect on implementation. The quality and strength of the evidence received the highest score. The dimension of the external context had a negative influence on the implementation of the intervention.

CONCLUSION

The objective of the study was to analyze the influence of contextual elements on the implementation process of a community-based dengue fever intervention. We used the CFIR framework already used by many studies for implementation analysis. Although it was not possible to test this framework in its entirety, it is useful for the analysis of the implementation. Its use is simple and does not require any special skills from users. Usability is indeed an essential criterion for the relevance of using an analytical framework in implementation science.

Assessment of Aedes aegypti (Diptera: Culicidae) Males Flight Ability for SIT Application: Effect of Device Design, Duration of Test, and Male Age

The Sterile Insect Technique (SIT) is a pest control method where large numbers of sterile males are released to induce sterility in wild populations. Since a successful SIT application depends on the released sterile males being competitive with wild males, standard quality control tests are a necessary component of any SIT program. Flight ability (ability to fly out from a device) is a reliable indicator of insect quality. Based on previous studies, we developed four new tubular devices constructed with locally available materials to explore their potential as flight test devices for Aedes aegypti (L.) mass-reared males. Males were allowed to fly upwards through a vertical tube, the ones that flew out were considered successful. The effect of male age (0 to 21 d old), test time interval (30 min to 24 h), and the design of the device (40 and 80 cm height and 2 and 3.5 cm diameter) were evaluated. Our devices determined differences in the flight ability of Ae. aegypti males of different ages. During the first minutes, more old males escaped than young males in three out of four types of devices. However, young males reached higher rates of escape in all cases after 24 h. For standard quality control tests, we recommend testing 2- to 3-d-old sexually mature males in the high and narrow device (80 × 2 cm). Further observations for time intervals between 1 and 5 h might be performed to decide the shortest and more representative interval to use.

Sustainable, healthy cities: protocol of a mixed methods evaluation of a cluster randomized controlled trial for Aedes control in Brazil using a community mobilization approach

Background

Dengue is increasing in its global presence with an estimated 4 billion people at-risk of infection in at least 128 countries. Despite the promising results of EcoHealth and community mobilization approaches to Aedes reduction, more evidence of their efficacy on reducing dengue risk is needed. The principal research question is to determine if interventions based upon community mobilization reduce the risk of dengue virus infection among children 3 to 9 years old compared to usual dengue control practice in Fortaleza, Brazil.

Methods

The present study will follow a pragmatic cluster randomized controlled trial (cRCT) design with randomization at the census tract level with equal allocation to the two arms. In each arm, there will be 34 clusters of 86 children between 3 to 9 years old for an expected total of 5848 children enrolled in the study, assuming a risk reduction of 29.5% based upon findings from a previous multi-site cRCT. The primary outcomes are rates of anti-dengue Immunoglobulin G (IgG) seroconversion and adult female Aedes density. The intervention is based upon a participatory health research approach, Socializing Evidence for Participatory Action (SEPA), where the research evidence is used to foster community engagement and ownership of the health issue and solution. Following allocation, intervention communities will develop and implement their own solutions that will likely include a wide variety of collective events and media approaches. Data collection activities over a period of 3 years include household visits for blood collection, household surveys, and entomological surveys; and qualitative activities including focus groups, in-depth interviews, and document analysis to evaluate the process, acceptability, fidelity, and sustainability of the intervention. Study participants will be aware of their assignment and all research staff will be blinded although the intervention assignment will likely be revealed to field staff through interaction with participants.

Discussion

The results of our study will provide evidence on community mobilization as an intervention for dengue control. We anticipate that if community mobilization is effective in Fortaleza, the results of this study will help develop evidence-based vector control programs in Brazil, and also in other countries struggling with Aedes-transmitted diseases.

Trial registration

ISRCTN66131315, registration date: 1 October 2018.

Dengue vaccine development: status and future

Dengue, the most common arbovirus, represents an increasingly significant cause of morbidity worldwide, including in travelers. After decades of research, the first dengue vaccine was licensed in 2015: CYD-TDV, a tetravalent live attenuated vaccine with a yellow fever vaccine backbone. Recent analyses have shown that vaccine performance is dependent on serostatus. In those who have had a previous dengue infection, i.e., who are seropositive, the efficacy is high and the vaccine is safe. However, in seronegative vaccinees, approximately 3 years after vaccination the vaccine increases the risk of developing severe dengue when the individual experiences a natural dengue infection.

The World Health Organization recommends that this vaccine be administered only to seropositive individuals. Current efforts are underway to develop rapid diagnostic tests to facilitate prevaccination screening. Two second-generation dengue vaccine candidates, both also live attenuated recombinant vaccines in late-stage development, may not present the same limitations because of differences in the backbone used, but results of phase 3 trials need to be available before firm conclusions can be drawn.

Dengue is increasingly frequent in travelers, but the only licensed dengue vaccine to date can be used only in seropositive individuals. However, the vast majority of travelers are seronegative. Furthermore, the primary series of three doses given 6 months apart renders this vaccine difficult in the travel medicine context.

Cryo-Electron Microscopy Reveals That Sperm Modification Coincides with Female Fertility in the Mosquito Aedes aegypti

Manipulating mosquito reproduction is a promising approach to reducing mosquito populations and the burden of diseases they carry. A thorough understanding of reproductive processes is necessary to develop such strategies, but little is known about how sperm are processed and prepared for fertilization within female mosquitoes. By employing cryo-electron microscopy for the first time to study sperm of the mosquito Aedes aegypti, we reveal that sperm shed their entire outer coat, the glycocalyx, within 24 hours of being stored in the female. Motility assays demonstrate that as their glycocalyx is shed in the female’s sperm storage organs, sperm transition from a period of dormancy to rapid motility—a critical prerequisite for sperm to reach the egg. We also show that females gradually become fertile as sperm become motile, and that oviposition behavior increases sharply after females reach peak fertility. Together, these experiments demonstrate a striking coincidence of the timelines of several reproductive events in Ae. aegypti, suggesting a direct relationship between sperm modification and female reproductive capacity.

'Swimming mosquitoes': a key stepping stone to prevent Dengue, Zika and Chikungunya: an educative experience in Colima, Mexico

Dengue, Zika and Chikungunya arboviruses (DZC), mainly transmitted by mosquito Aedes aegypti, are global health public issues affecting 390 million people each year. In most endemic countries, vector control strategies have been focused on reducing breeding sites and adult mosquito populations. Most health communication strategies have pointed out adult mosquito as the main responsible of the transmission, persuading people to eliminate domestic containers. However, it is not clear how should people understand the relationship between adult mosquitoes and water domestic containers. So, the main goal of the present study was to assess the people understanding of this relationship. Results showed that most people associate adult mosquitoes with DZC, but only few could associate swimming larvae with mosquitoes. The unawareness of larva presence leads to an underestimation of risk perception about DZC transmission. In this context, we consider that educative interventions for health promotion, based on meaningful knowledge and social representations arise as long-term strategies to control transmission of vector-borne diseases. Here, we propose innovative health strategies focused on increase the risk perception about swimming larvae, considering social representations, which may be a key stepping stone to increase people adherence to massive campaigns and reducing DZC burden.

Serologic Tools and Strategies to Support Intervention Trials to Combat Zika Virus Infection and Disease

Zika virus is an emerging mosquito-borne flavivirus that recently caused a large epidemic in Latin America characterized by novel disease phenotypes, including Guillain-Barré syndrome, sexual transmission, and congenital anomalies, such as microcephaly. This epidemic, which was declared an international public health emergency by the World Health Organization, has highlighted shortcomings in our current understanding of, and preparation for, emerging infectious diseases in general, as well as challenges that are specific to Zika virus infection. Vaccine development for Zika virus has been a high priority of the public health response, and several candidates have shown promise in pre-clinical and early phase clinical trials. The optimal selection and implementation of imperfect serologic assays are among the crucial issues that must be addressed in order to advance Zika vaccine development. Here, I review key considerations for how best to incorporate into Zika vaccine trials the existing serologic tools, as well as those on the horizon. Beyond that, this discussion is relevant to other intervention strategies to combat Zika and likely other emerging infectious diseases.

Which green way: description of the intervention for mobilising against Aedes aegypti under difficult security conditions in southern Mexico

Background

Community mobilisation for prevention requires engagement with and buy in from those communities. In the Mexico state of Guerrero, unprecedented social violence related to the narcotics trade has eroded most community structures. A recent randomised controlled trial in 90 coastal communities achieved sufficient mobilisation to reduce conventional vector density indicators, self-reported dengue illness and serologically proved dengue virus infection.

Methods

The Camino Verde intervention was a participatory research protocol promoting local discussion of baseline evidence and co-design of vector control solutions. Training of facilitators emphasised community authorship rather than trying to convince communities to do specific activities. Several discussion groups in each intervention community generated a loose and evolving prevention plan. Facilitators trained brigadistas, the first wave of whom received a small monthly stipend. Increasing numbers of volunteers joined the effort without pay. All communities opted to work with schoolchildren and for house-to-house visits by brigadístas. Children joined the neighbourhood vector control movements where security conditions permitted. After 6 months, a peer evaluation involved brigadista visits between intervention communities to review and to share progress.

Discussion

Although most communities had no active social institutions at the outset, local action planning using survey data provided a starting point for community authorship. Well-known in their own communities, brigadistas faced little security risk compared with the facilitators who visited the communities, or with governmental programmes. We believe the training focus on evidence-based dialogue and a plural community ownership through multiple design groups were key to success under challenging security conditions.

Trial registration

ISRCTN27581154.

Household costs for personal protection against mosquitoes: secondary outcomes from a randomised controlled trial of dengue prevention in Guerrero state, Mexico

BACKGROUND

Dengue is a serious public health issue that affects households in endemic areas in terms of health and also economically, imposing costs for prevention and treatment of cases. The Camino Verde cluster-randomised controlled trial in Mexico and Nicaragua assessed the impact of evidence-based community engagement in dengue prevention. The Mexican arm of the trial was conducted in 90 randomly selected communities in three coastal regions of Guerrero State. This study reports an analysis of a secondary outcome of the trial: household use of and expenditure on anti-mosquito products. We examined whether the education and mobilisation activities of the trial motivated people to spend less on anti-mosquito products.

METHODS

We carried out a household questionnaire survey in the trial communities in 2010 (12,312 households) and 2012 (5349 households in intervention clusters, 5142 households in control clusters), including questions about socio-economic status, self-reported dengue illness, and purchase of and expenditure on insecticide anti-mosquito products in the previous month. We examined expenditures on anti-mosquito products at baseline in relation to social vulnerability and we compared use of and expenditures on these products between intervention and control clusters in 2012.

RESULTS

In 2010, 44.2% of 12,312 households reported using anti-mosquito products, with a mean expenditure of USD4.61 per month among those who used them. Socially vulnerable households spent less on the products. In 2012, after the intervention, the proportion of households who purchased anti-mosquito products in the last month was significantly lower in intervention clusters (47.8%; 2503/5293) than in control clusters (53.3%; 2707/5079) (difference - 0.05, 95% CIca -0.100 to -0.010). The mean expenditure on the products, among those households who bought them, was USD6.43; 30.4% in the intervention clusters and 36.7% in the control clusters spent more than this (difference - 0.06, 95% CIca -0.12 to -0.01). These expenditures on anti-mosquito products represent 3.3% and 3.8% respectively of monthly household income for the poorest 10% of the population in 2012.

CONCLUSIONS

The Camino Verde community mobilisation intervention, as well as being effective in reducing dengue infections, was effective in reducing household use of and expenditure on insecticide anti-mosquito products.

TRIAL REGISTRATION

( ISRCTN27581154 ).

Aedes aegypti breeding ecology in Guerrero: cross-sectional study of mosquito breeding sites from the baseline for the Camino Verde trial in Mexico

Background

Understanding the breeding patterns of Aedes aegypti in households and the factors associated with infestation are important for implementing vector control. The baseline survey of a cluster randomised controlled trial of community mobilisation for dengue prevention in Mexico and Nicaragua collected information about the containers that are the main breeding sites, identified possible actions to reduce breeding, and examined factors associated with household infestation. This paper describes findings from the Mexican arm of the baseline survey.

Methods

In 2010 field teams conducted household surveys and entomological inspections in 11,995 households from 90 representative communities in the three coastal regions of Guerrero State, Mexico. We characterized Ae. aegypti breeding sites and examined the effect of two preventive measures: temephos application in water containers, and keeping the containers covered. We examined associations with household infestation, using bivariate and multivariate analysis adjusted for clustering effects.

Results

We conducted entomological inspections in 11,995 households. Among 45,353 water containers examined, 6.5% (2958/45,353) were positive for larvae and/or pupae. Concrete tanks (pilas) and barrels (tambos) together accounted for 74% of pupal productivity. Both covering water containers and inserting temephos were independently associated with a lower risk of presence of larvae or pupae, with the effect of covering (OR 0.22; 95% CIca 0.15–0.27) stronger than that of temephos (OR 0.66; 95% CIca 0.53–0.84). Having more than four water containers was associated with household infestation in both rural areas (OR 1.42; 95% CIca 1.17–1.72) and urban areas (1.81; 1.47–2.25), as was low education of the household head (rural: 1.27; 1.11–1.46, and urban: 1.39; 1.17–1.66). Additional factors in rural areas were: household head without paid work (1.31; 1.08–1.59); being in the Acapulco region (1.91; 1.06–3.44); and using anti-mosquito products (1.27; 1.09–1.47). In urban areas only, presence of temephos was associated with a lower risk of household infestation (0.44; 0.32–0.60).

Conclusion

Concrete tanks and barrels accounted for the majority of pupal productivity. Covering water containers could be an effective means of Ae. aegypti vector control, with a bigger effect than using temephos. These findings were useful in planning and implementing the Camino Verde trial intervention in Mexico.

Mobilising communities for Aedes aegypti control: the SEPA approach

Abstract

Camino Verde (the Green Way) is an evidence-based community mobilisation tool for prevention of dengue and other mosquito-borne viral diseases. Its effectiveness was demonstrated in a cluster-randomised controlled trial conducted in 2010–2013 in Nicaragua and Mexico. The common approach that brought functional consistency to the Camino Verde intervention in both Mexico and Nicaragua is Socialisation of Evidence for Participatory Action (SEPA).

In this article, we explain the SEPA concept and its theoretical origins, giving examples of its previous application in different countries and contexts. We describe how the approach was used in the Camino Verde intervention, with details that show commonalities and differences in the application of the approach in Mexico and Nicaragua. We discuss issues of cost, replicability and sustainability, and comment on which components of the intervention were most important to its success. In complex interventions, multiple components act in synergy to produce change. Among key factors in the success of Camino Verde were the use of community volunteers called brigadistas, the house-to-house visits they conducted, the use of evidence derived from the communities themselves, and community ownership of the undertaking.

Communities received the intervention by random assignment; dengue was not necessarily their greatest concern. The very nature of the dengue threat dictated many of the actions that needed to be taken at household and neighbourhood levels to control it. But within these parameters, communities exercised a large degree of control over the intervention and displayed considerable ingenuity in the process.

Trial registration

ISRCTN27581154.

Household costs of dengue illness: secondary outcomes from a randomised controlled trial of dengue prevention in Guerrero state, Mexico

Background

Dengue is a serious public health problem with an important economic impact. This study used data from a cluster randomised controlled trial of community mobilisation for dengue prevention to estimate the household costs of treatment of dengue illness. It examined the economic impact of the trial intervention in the three coastal regions of Mexico’s Guerrero State.

Methods

The 2010 baseline survey covered households in a random sample of 90 clusters in the coastal regions; the clusters were randomly allocated to intervention or control and re-surveyed in 2012. The surveys asked about dengue cases in the last 12 months, expenditures on their treatment, and work or school days lost by patients and care givers. We did not assign monetary value to days lost, since a lost day to a person of low earning power is of equal or higher value to that person than to one who earns more.

Results

The 12,312 households in 2010 reported 1020 dengue cases in the last 12 months (1.9% of the sample population). Most (78%) were ambulatory cases, with a mean cost of USD 51 and 10.8 work/school days, rising to USD 96 and 11.4 work/school days if treated by a private physician. Hospitalised cases cost USD 28–94 in government institutions and USD 392 in private hospitals (excluding additional inpatient charges), as well as 9.6–17.3 work/school days. Dengue cases cost households an estimated 412,825 work/school days throughout the three coastal regions. In the follow up survey, 6.1% (326/5349) of households in intervention clusters and 7.9% (405/5139) in control clusters reported at least one dengue case. The mean of days lost per case was similar in intervention and control clusters, but the number of days lost from dengue and all elements of costs for dengue cases per 1000 population were lower in intervention clusters. If the total population of the three coastal regions had received the intervention, some 149,401 work or school days lost per year could have been prevented.

Conclusion

The economic effect of dengue on households, including lost work days, is substantial. The Camino Verde trial intervention reduced household costs for treatment of dengue cases.

Trial registration

The trial was registered as ISRCTN:27,581,154.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4304-x) contains supplementary material, which is available to authorized users.

Randomised controlled trials and changing public health practice

One reason for doing randomised controlled trials (RCTs) is that experiments can be convincing. Early epidemiological experimenters, such as Jenner and the smallpox vaccine and Snow and his famous Broad Street pump handle, already knew the answer they were demonstrating; they used the experiments as knowledge translation devices to convince others.

More sophisticated modern experiments include cluster randomised controlled trials (CRCTs) for experiments in the public health setting. The knowledge translation value remains: RCTs and CRCTs can potentially stimulate changes of practice among stakeholders. Capitalising on the knowledge translation value of RCTs requires more than the standard reporting of trials. Those who are convinced by a trial and want to act, need to know how the trial relates to their own context, what contributed to success, and what might make it even more effective. Implementation research unpacks the back-story, examining how and why an intervention worked.

The Camino Verde trial of community mobilisation for control of dengue reported a significant impact on entomological indices of the Aedes aegypti vector, and on serological dengue virus infection and self-reported dengue cases. This important study should lead to studies of similar interventions in other contexts, and ultimately to changes in dengue control practices. This supplement is the back-story of the trial, providing information to help researchers and planners to make use of the trial findings.

Background articles include the full protocol, a systematic review of CRCTs of approaches for Aedes aegypti control, epidemiological and entomological findings from the baseline survey, and how baseline findings were used to set up the intervention. Secondary analyses of the entomological findings examine associations with the use of the larvicide temephos, and the impact of the intervention in different conditions of water supply and seasons.

Other articles describe implementation and other impacts: the underlying approach; implementation in the trial’s different social contexts; the different impact in women and men; the effects of using fish for vector control; the impact on household costs of personal protection and of cases of dengue illness; and ethical issues.

We hope this supplement will increase the knowledge translation value of the Camino Verde trial.

Community cost-benefit discussions that launched the Camino Verde intervention in Nicaragua

BACKGROUND

Recent literature on community intervention research stresses system change as a condition for durable impact. This involves highly participatory social processes leading to behavioural change.

METHODS

Before launching the intervention in the Nicaraguan arm of Camino Verde, a cluster-randomised controlled trial to show that pesticide-free community mobilisation adds effectiveness to conventional dengue controls, we held structured discussions with leaders of intervention communities on costs of dengue illness and dengue control measures taken by both government and households. These discussions were the first step in an effort at Socialising Evidence for Participatory Action (SEPA), a community mobilisation method used successfully in other contexts. Theoretical grounding came from community psychology and behavioural economics.

RESULTS

The leaders expressed surprise at how large and unexpected an economic burden dengue places on households. They also acknowledged that large investments of household and government resources to combat dengue have not had the expected results. Many were not ready to see community preventive measures as a substitute for chemical controls but all the leaders approved the formation of "brigades" to promote chemical-free household control efforts in their own communities.

CONCLUSIONS

Discussions centred on household budget decisions provide a good entry point for researchers to engage with communities, especially when the evidence showed that current expenditures were providing a poor return. People became motivated not only to search for ways to reduce their costs but also to question the current response to the problem in question. This in turn helped create conditions favourable to community mobilisation for change.

TRIAL REGISTRATION

ISRCTN27581154 .

Dengue occurrence relations and serology: cross-sectional analysis of results from the Guerrero State, Mexico, baseline for a cluster-randomised controlled trial of community mobilisation for dengue prevention

Background

The Mexican arm of the Camino Verde trial of community mobilisation for dengue prevention covered three coastal regions of Guerrero state: Acapulco, Costa Grande and Costa Chica. A baseline cross-sectional survey provided data for community mobilisation and for adapting the intervention design to concrete conditions in the intervention areas.

Methods

Trained field teams constructed community profiles in randomly selected clusters, based on observation and key informant interviews. In each household they carried out an entomological inspection of water containers, collected information on socio-demographic variables and cases of dengue illness among household members in the last year, and gathered paired saliva samples from children aged 3–9 years, which were subjected to ELISA testing to detect recent dengue infection. We examined associations with dengue illness and recent dengue infection in bivariate and then multivariate analysis.

Results

In 70/90 clusters, key informants were unable to identify any organized community groups. Some 1.9% (1029/55,723) of the household population reported dengue illness in the past year, with a higher rate in Acapulco region. Among children 3–9 years old, 6.1% (392/6382) had serological evidence of recent dengue infection. In all three regions, household use of anti-mosquito products, household heads working, and households having less than 5 members were associated with self-reported dengue illness. In Acapulco region, people aged less than 25 years, those with a more educated household head and those from urban sites were also more likely to report dengue illness, while in Costa Chica and Costa Grande, females were more likely to report dengue illness. Among children aged 3–9 years, those aged 3–4 years and those living in Acapulco were more likely to have evidence of recent dengue infection.

Conclusions

The evidence from the baseline survey provided important support for the design and implementation of the trial intervention. The weakness of community leadership and the relatively low rates of self-reported dengue illness were challenges that the Mexican intervention team had to overcome. The higher dengue illness occurrence among women in Costa Grande and Costa Chica may help explain why women participated more than men in activities during the Camino Verde trial.